This application relates to an intelligent digital thermometer, e.g., for measuring, recording, and/or charting a person's body temperature. One potentially useful application of taking body temperature measurements is to monitor a women's basal body temperature (“BBT”), which is generally defined as the lowest body temperature attained during rest (usually during sleep). BBT is generally measured immediately after awakening and before any physical activity has been undertaken, although the temperature measured at that time is somewhat higher than the true basal body temperature (see FIG. 1, which shows an example of a biphasic basal body temperature chart). In women, ovulation causes an increase of one-half to one degree Fahrenheit (one-quarter to one-half degree Celsius) in BBT; monitoring of BBT is one way of estimating the day of ovulation. The tendency of a woman to have lower temperatures before ovulation, and higher temperatures afterwards, is known as a biphasic pattern. Charting of this pattern may be used as a component of fertility awareness. Accordingly, a women seeking fertility awareness may find it productive to measure her BBT once a day over a period of several days, chart the measurements on a graph and then examine the resulting charts to determine whether an increase in BBT is indicated.